“One of the oldest harbours documented in Southern Africa, medieval Sofala was erected on the edge of a wide estuary formed by the Buzi River (called Rio de Sofala in older maps). The Somali merchants from Mogadishu, the capital of the Ajuran Empire, established a colony in Mozambique to extract gold from the mines in Sofala.[2]”
https://en.m.wikipedia.org/wiki/Sofala
https://en.m.wikipedia.org/wiki/Sofala